Indicator system with signal indicators

ABSTRACT

An indicator system with signal indicators arranged in lines and columns, each indicator having a stepping motor and a release relay and being interconnected through control switches to require a minimum of interconnecting wiring. A switch means is provided in each signal indicator, and is actuated by the release relay.

[4 1 Feb. 11,1975

United States Patent "[191 Tschumi INDICATOR SYSTEM WITH SIGNALINDICATORS [5 6] References Cited UNITED STATES PATENTS [75] Inventor:Otto TschumLSolothurn,

Switzerland vAssignee: Autophon Aktiengesellschaft,

3,491,354 l/l970 Tschumi 340/324 Solothurn, Switzerland PrimaryExaminer-G. R. Simmons 3 7 9 l 6 0 n t5 0 04 o N .ml 0. MP FA NH 22 llForeign Application Priority Data terconnecting wiring. A switch meansis provided in each signal indicator, and is actuated by the releaserelay.

m 6 9 W 6 4 O 8 5 l l 3 m 5 m 2 n 3 i m 0 u 4 H 3 n a m 9 U 7 m B 3 A H3 Z .R n w m S H 2 m 7 u 9 m l m C a S O U T 5 I [51] Int. Cl. G08b 5/00340/324, 325, 378, 379;

[58] Field of Search 318/685, 696, 440 10 Claims, 8 Drawing FiguresPATENTEU FEB] 1 5 SHEET 2 0F 2 Fig; 4

Fig.2

INDICATOR SYSTEM WITH SIGNAL INDICATORS This invention relates to anindicator system with signal indicators arranged in lines and columns.The signal indicators are each provided with a stepping motor having twoconductors and which powers arotary signal indicator. These indicatorsare in the form of an interchangeable mechanical unit. A known signalindicator is disclosed, for example, in Swiss Pat No. 386,297. In such aknown system, only signal indicators relating to a particular linereceive power supply which feeds the signal indicators of a plurality oflines via a column circuit with a common ground. This is achieved byconnecting one conductor of the stepping motor of all signal indicatorsto the common ground and to connect the other conductor of each unitwith one respective switch which connects it to its respective columncircuit. The switches mentioned, relating to a line of signalindicators, will be operated by common control devices and powered by apower supply, so that a line of signal indicators can be adjustedthrough currents fed through the respective column circuits.

The switch means relating to each signal indicator is in the form of arelay contact. Each line must be equipped with a number of relays,depending upon the maximum number of contacts per relay that can beutilized. The space requirement for the relays is usually the source ofatroublesome problem. The relays can be located so as to provide easyaccess and maintenance, but in that case the wiring to the relays andrelay contacts extending to the signal indicators, are usually requiredto be long and extensive. If the wiring is to be made less extensive,the result will of necessity be an arrangement of the relays in a manneror disposition in which ready access and maintenance are difficult.

To avoid the need for a multitude of contacts, solutions have been foundin the prior art, as for example in Swiss Pat. No. 514,210, where onlyone or two contacts are used, in addition to rectifiers. The prior artshows that contacts, moreover can be replaced by thyristors, where thespace and placement requirement is insignificant. Such designs, however,have the disadvantage that feeder lines for lines and columns which arenot operative may be powered by operating voltages if maintenance isrequired. This can lead to major complications and damage if duringmaintenance operations, shorts between wires and frame occur while otherparts of thesystem are operating; thus the damage can be far greater insuch an arrangement than in a system where each signal indicator isprovided with its respective relay contact.

It is the object of the present invention to provide an indicator systemretaining the advantages which are offered by placing switch means foroperating a signal indicator into one column circuit; and reducing theextent of wiring with a consequent reduction in the total wiring cost.The invention relates to a system which is characterized by placing theswitch means into each signal indicator.

In systems with signal indicators provided with a locking device and arelease relay or a release magnet, very advantageous versions of theinvention are feasible. In one of these versions, the release relay isused for operating the switch means, therefore, no separate coil isrequired. In others it is possible to avoid need for separate wiring tooperate the switch means.

Having reference to the accompanying drawings:

FIG. 1 shows a wiring diagram portion of an indicator system. The signalindicators are arranged and shown by way of illustration in three linesand in three columns, but this is not by way of limitation. Only one of5 the signal indicators is shown in detail, the others are simplified.

FIGS. 2 to 7 show schematics of other signal indicator designs.

FIG. 8 is a perspective representation of a switching relay which willoperate in the complete signal indicator a locking device of the signalcarrier as well as the switch which will actuate the stepping motor.

The nine signal indicators ZM shown schematically in FIG. 1 areinterchangeable mechanical units of identical design. The signalindicator shown in the upper left discloses schematically more detailthan is shown for the others. Each signal indicator ZM is provided witha stepping motor with a coil M having two conductors and a rotor A witha permanent magnet. This motor will make half a turn if coil M isenergized with impulses of alternating polarity and will drive a signalcarrier ZT rotating around shaft X via a gear transmission. This signalindicator, of which merely one disc is shown, preferably consists of theordinary drum type containing the signals or signs to be displayed. Witheach half turn of the stepping motor one of the signals or signs will beturned and another signal will be displayed. On the disc shown of signalindicator ZT, a pin B is disposed in a manner that its rotary path willinterfere with latch SH. Therefore, the signal indicator has a lockedposition preventing further rotation. Further rotation only can occurwhen latch SH will be moved out of the path of movement of pin B throughexcitation of release relay F which, in turn, is provided with twoconductors. By means of this locking and release device, a signalindicator in an unknown arbitrary position can be moved back by acontrol device to an initial known position, from where another desiredposition can be chosen by counting the number of impulses fed to thestepping motor.

One example of the release relays used in FIG. 1 is shown in FIG. 8.Such a relay is provided with a coil F, a yoke 2 and mounted on it isarmature l which will operate latch SI-I with its back portion 5. LatchSI-I also is pivotally supported but not shown here.

In FIG. 1 these details are shown simplified and the latch and armatureare shown as one single piece. The front portion of the coil is providedwith an extension 3 formed of a magnetic material. At the back portionof the yoke 2, which is the opposing magnetic pole, a similar extension4 has been provided. Both extensions are designed with tabs 6 enclosingswitch SK. The release relay, therefore, involves two magnetic circuits.The first circuit is formed through yoke 2 and armature 1. The secondcircuit is formed through extensions 3 and 4 and the switch means SK,therebetween. The two magnetic circuits serve to actuate latch SH andalso the switch means SK. The magnetic conditions and the opposing forcewhen the armature is attracted are chosen such that a threshold valueexists. This means that under weak coil excitation, only switch means SKis closed and the armature remains in its open position; while understronger excitation, the armature also will be attracted and will causeoperation of latch SH.

One of the stepping motor conductors of each of the signal indicators ZMis interconnected and connected to one of the conductors of each releaserelay F and then to a common conductor which is connected to ground. Theother conductor of each stepping motor M is connected to the respectivecolumn circuit Kl K3 via the respective switch means SK. The otherconductor of each release relay F contained in a particular line ofsignal indicators are all connected to a common line circuit Z1 Z3.Through this arrangement, all switch means SK of a particular line canbe operated simultaneously.

A power supply SP energizing the entire system is provided with fourconductors. The first conductor is connected to ground. Conductors +1and -1 supply a relatively low voltage each being of equal potential,but opposite polarity. Conductor +2, however, is of a relatively highvoltage. The voltages at conductor +1 and 1 are selected to besufficient for the operation of the stepping motor M and for theoperation of switch means SK, but inadequate for unlocking latch SH.Supplying a voltage +2 to the coil F causes operation of switch means SKand also the operation oflatch SH and therefore the release of thesignal carrier.

By means of the electronic switches K+ and K, conductors +1 and 1 can beconnected to the common column conductor KSS, which in turn can beconnected selectively to the three column circuits K1 K3 throughswitches KS1 KS3. Choosing suitable combinations of these switches,therefore, selectively connects each column circuit to voltage +1 or 1.

The line circuits Z1 Z3 are selectively connectable to voltage +1through the electronic switches SS1 SS3, also to voltage +2 through lineswitches FSl FS3. As explained previously, supplying voltage +1 to aline circuit will operate all switch means SK in signal indicators of arespective line; supplying the voltage +2 will actuate switch means SKand also the latch SH. Both of these operations consequently arecontrolled over the same conductor. Supplying different voltages willcause different currents in respective coils. A separate conductor forthe operation of switch SK, therefore, can be omitted.

The control device ST is basically a programmer which consists of afixed program and an additional changing program containing theinformation to be indicated, and will supply control criteria for theoperation of the electronic switches explained before. Based on theposition of these switches, the release relays of the new line willreceive voltages through the linecircuits Z on one hand and the steppingmotors M adjusting to a new position through the column circuit K1 K3 onthe other hand, which they will in turn need to carry out the requiredfunction.

The nine signal indicators ZM shown in FIG. 1 will be adjusted per lineby control device ST. Should a signal indicator be adjusted in a givenline, for example, the second one, control device ST gives command tooperate switch SS2 whereby supply voltage +1 will be connected to linecircuit Z2. Consequently, a weak current will be passed through therelease relay F of all signal indicators belonging to the second line.This will actuate switch means SK in all signal indicators of thissecond line; however, it leaves the latches in their locked positions.Each motor coil M of the second line is now connected to its respectivecolumn circuit Kl K3 via switch means SK contained in each individualsignal indicator.

Besides closing switch SS2, the control device ST also will close columnswitch KS1 KS3 and therefore, prepare all signal indicators of thesecond line for receiving inpulses. Subsequently, control device ST willalternately operate the switches K+ and K-. Alternating pulses fromconductors +1 and -1 of power supply SP will be fed to the motors ofrespective signal indicators and from there to ground, over the threecolumn circuits K1 K3 and the switch means SK contained in signalindicators of the second line, whereby the motors will turn until pins Bof all respective signal indicators will strike latches SH.

After this condition of an initial starting position has been reached,the control device ST will open switch SS2 and close F82, wherebyvoltage +2 will be supplied to line circuit Z2. In coils F of the signalindicators of line 2, a larger current will flow now than previously,which not only will operate switch means SK, but also will bring latchesSH into their releasing positions, so that the signal indicators cancontinue to turn During the period which follows, the control device STwill operate switches K+ and K in the same fashion as before, but willoperate column switch KS1 KS3 in a way which depends on the signal orsign to be indicated in line 2. Each of these switches will be held in aclosed position during a certain time, that is when motor M of therespective column and the second line will receive a certain number ofpulses from switches K+ and K, so that the signal indicator will turn toa signal or sign to be shown. Since ordinarily different signals will beexhibited by different signal indicators of a particular line, the timerequired when switches KS will be in their closed position, will alsodiffer. Either all switches KS1 KS3 can be closed simultaneously or allswitches can be closed in such a way that the adjustment of a particularline of signal indicators will be completed simultaneously. Aftercompleting a certain setting, the control device will bring allelectronic switches into the locked position and then it is ready for anadjustment of a new line.

FIGS. 2 7 show schematics of signal indicators which will be used in sixalternate designs of indicator systems. Although the line and columncircuitry in these examples does not match completely with that of FIG.1, they are not explained here and not shown, because in the context ofthe explained first design all essential characteristics of thesesystems can be understood without further explanation. The differencesof the signal indicators shown in FIGS. 2 7 versus those of FIGS. 1 and8 are in alternate switch means connecting the stepping motors withtheir respective column circuits and way of operating these switchmeans.

In signal indicators as represented by FIGS. 2, 3 and 4, a relay A isused as switch means to connect column circuit K1 K3 with the motor M ofthe respective column. A relay of any known design can be used. In thefirst two design examples, each relay is connected to a line circuit ZAwhich controls exclusively the relay of the signal indicators of aparticular line. The signal indicator of FIG. 2 is not provided with alocking device and a release relay, while the signal indicator of FIG. 3is provided with release relay F independent of relay A and fedindependently by line circuit ZF. Here two lines circuits are requiredand the signal indicators require one more conductor each than those ofFIG. 1.

In signal indicators of FIG. 4, however, only one line circuit Z andthree conductors are required, despite the additional equipment of aseparate relay and a release relay. In this example, the relay A andrelease relay F are operated over the same line circuit Z. The selectionof the device will be determined by the direction of current flow, asdetermined by a rectifier G1 in series with release relay F. The relaycan be operated only if line circuit 2 carries a positive voltagerelative to ground at E. The relay A, however, closes switch means SK ifa voltage of arbitrary polarity is being supplied. In a system withthese signal indicators, therefore, the control device can operate therespective signal indicators of a line by supplying a voltage ofnegative polarity to the line circuit and hence will operate relay Aonly, but by supplying a positive voltage, it will operate relay A andrelay F together.

The signal indicator as represented by FIG. 5 is provided with a releaserelay as shown in FIG. 8 and explained in the system of FIG. 1.

Switch means SK are designed similarly in that system. Below a certainthreshold value of magnetic excitement of the release relay, only switchmeans SK will be operated, but when excitement above said thresholdoccurs, the latch will be operated over the same conductor. In contrastto FIG. 1, however, it is not the different currents caused by differentvoltages that will effect the different values, but rather voltages ofdifferent polarity. This will be achieved by positioning a rectifier G2and resistor R1 parallel to each other in series to the release relay F.When supplying a positive voltage to line circuit Z, the resistor R1 isbypassed, and therefore, the current is large. A supply of a negativevoltage creates a small current being only that passed through R1. Thevalue of R1 is determined by the operating voltage, the threshold valueof the latch and the switch SK, so that the larger current is adequateto unlatch and operate the motor while the smaller current just operatesthe motor.

FIGS. 6 and 7 shows designs of signal indicators where the switch meansSK, connecting the motor to its respective column conductor, arereplaced by one or two thyristors. These signal indicators again includea release relay F. Over the same conductor, which is line circuit Z, thelatch can be operated. As well, the thyristor can be changed to itsconductive condition. In one system as it is shown in FIG. 6, twothyristors T1, T2, are switched antiparallel. The thyristors areswitched by an A.C. voltage supplied over line circuit Z.

To accomplish this inside the signal indicator, a transformer U isprovided with its primary side parallel to coil F of the release relay.The capacitor C in series to the transformer coil prevents a flow ofdirect current. The transformer is provided with two secondary coils,the first in series with a resistor R2 between cathode and switchingelectrode of thyristor T1, while the secondary coil along with resistorR3 has the same effect on thyristor T2. If no A.C. voltage existsbetween line circuit Z and ground E, no current can flow. If an A.C.voltage, preferably in audible frequency range, is supplied, boththyristors will be constantly supplied with a switching voltage, so thatbetween column circuit K and motor M, currents can flow in eitherdirection. The release relay F of a line will be operated when a DC.voltage will be supplied to the respective line circuit Z. Since theexcitement in release relay is only adequate if the thyristor will beswitching, the DC. voltage has to be superimposed over the A.C. voltage.Basically coil F could be used as transformer.

The two-way thyristor ZT inserted as switching means into the signalindicator of FIG. 7 requires a positive voltage against ground at itsswitching electrode to permit currents to flow in either direction. Thisswitching electrode is connected to line circuit Z over a resistor R4.Since the coil of release relay F is wired between line circuit andground, no voltage is present between motor M, the connected electrodeof the thyristor and the switching electrode, unless the line circuit issupplied with a voltage. This means that in this condition the thyristoris blocked for current flow in either direction. To operate the motorsof a line of signal indicators between column circuit K, a positivevoltage to the respective line circuit Z is required, whereby in eachsignal indicator of the respective line the switching electrode of thethyristor will become positive through resistor R4 and against motor M;thus the thyristor will switch or ignite and allow current flow ineither direction. The value of resistors R4 are determined such that onone side the thyristors will respond when a voltage is supplied to linecircuit Z, while the release relays which are also connected to the linecircuit will not respond. On the other hand, the voltage required tooperate the release relays is still an allowable current for theswitching or ignition electrode of the thyristor. In this design, likethat shown in FIGS. 1 and 8, the voltage level supplied to line circuitZ either can result in switching column circuits K and the motor or thelatter including the release of the latch mechanism. To reduce thedifferential of the voltages required, a Zener diode in series with coilF of release relay F could be provided, which would have to be sizedaccording to the coil.

The arrangement of switch means SK inthe interchangeable mechanicalunits of signal indicators permits a minimum of wiring in an indicatorsystem. A defect in a switch SK can only affect the respective signalindicator and, therefore, can be eliminated easily by exchanging thewhole signal indicator. It is to be understood that the invention is notlimited to the designs shown. Without leaving the idea of the invention,more solutions could be arranged by various combinations ofpossibilities shown in the examples. The invention also should not belimited to the application of stepping motors by movement throughimpulses of alternating polarity.

What is claimed is:

1. An indicator system comprising a plurality of interchangeable signalindicators each being placed in respective rows and columns and having astepping motor with two conductors and a rotatable signal carriermechanically driven by said stepping motor, and a mechanical stop forstopping said signal carrier in a defined position, and arelease magnetfor releasing said mechanical stop, a power supply for providing acommon potential to one of the conductors of each stepping motor and tosaid release magnet and a predetermined voltage potential to a pluralityof column conductors to which the other conductor of all signalindicators of the respective column can be connected, said power supplyfurther adapted to supply a predetermined voltage potential to one sideof each said release magnet of a selected row, a stepping motor switchmeans connecting each respective stepping motor to its respective columnconductor, and a column control switch means interconnecting said powersupply means to each respective column conductor, said stepping motorswitch means being disposed within each signal indicator and beingadapted for actuation in response to certain energization of saidrelease magnet.

2. An indicator system as claimed in claim 1 characterized in that saidstepping motor switch means and said release magnet are designed with athreshold characteristic as to enable actuation of said stepping motorswitch means at one potential of applied voltage, and actuation of bothsaid stepping motor switch means and said release magnet at anotherpotential of applied voltage.

3. An indicator system as claimed in claim 2 characterized in that saidrelease magnet comprises a single magnetic coil and separate magneticcircuit for actuating said stepping motor switch means and saidmechanical stop.

4. An indicator system as claimed in claim 3 comprising a resistor and arectifier connected in parallel with each other and in series with thecoil of said release magnet to produce different values of energizingcurrent in response to the polarity of voltage applied thereto.

5. An indicator system as claimed in claim 3 wherein said stepping motorswitch means comprise reed contacts.

6. An indicator system as claimed in claim 1 wherein said stepping motorswitch means consist of thyristors.

7. An indicator system as claimed in claim 1 characterized in that saidpower supply is adapted to supply impulses of alternating polarity todrive said stepping motor, said stepping motor switch means consistingof thyristors connected in anti-parallel.

8. An indicator system as claimed in claim 1 characterized in that saidpower supply is adapted to supply impulses of alternating polarity, saidstepping motor switch means comprising a two way thyristor (triac).

9. An indicator system as claimed in claim I comprising a row conductorfor each row of signal indicators, each signal indicator having firstand second row switch means for each row, the first row switch meansconnecting the respective row conductor to a predetermined first voltagepotential and the second row switch means connecting the respective rowconductor to a predetermined second voltage potential of saidpowersupply, said release magnet being adapted to actuate only saidstepping motor switch means upon actuation by said first voltagepotential and being further adapted to actuate both the stepping motorswitch means and said release magnet upon actuation by said secondvoltage potential.

10. An indicator system as claimed. in claim 9 wherein said steppingmotor switch means and the release magnet are connected in a manner suchthat the stepping motor switch means are actuated in response toenergization of either polarity and the release magnet is actuated onlyin response to energization of a single polarity.

1. An indicator system comprising a plurality of interchangeable signalindicators each being placed in respective rows and columns and having astepping motor with two conductors and a rotatable signal carriermechanically driven by said stepping motor, and a mechanical stop forstopping said signal carrier in a defined position, and a release magnetfor releasing said mechanical stop, a power supply for providing acommon potential to one of the conductors of each stepping motor and tosaid release magnet and a predetermined voltage potential to a pluralityof column conductors to which the other conductor of all signalindicators of the respective column can be connected, said power supplyfurther adapted to supply a predetermined voltage potential to one sideof each said release magnet of a selected row, a stepping motor switchmeans connecting each respective stepping motor to its respective columnconductor, and a column control switch means interconnecting said powersupply means to each respective column conductor, said stepping motorswitch means being disposed within each signal indicator and beingadapted for actuation in response to certain energization of saidrelease magnet.
 2. An indicator system as claimed in claim 1characterized in that said stepping motor switch means and said releasemagnet are designed with a threshold characteristic as to enableactuation of said stepping motor switch means at one potential ofapplied voltage, and actuation of both said stepping motor switch meansand said release magnet at another potential of applied voltage.
 3. Anindicator system as claimed in claim 2 characterized in that saidrelease magnet comprises a single magnetic coil and separate magneticcircuit for actuating said stepping motor switch means and saidmechanical stop.
 4. An indicator system as claimed in claim 3 comprisinga resistor and a rectifier connected in parallel with each other and inseries with the coil of said release magnet to produce different valuesof energizing current in response to the polarity of voltage appliedthereto.
 5. An indicator system as claimed in claim 3 wherein saidstepping motor switch means comprise reed contacts.
 6. An indicatorsystem as claimed in claim 1 wherein said stepping motor switch meansconsist of thyristors.
 7. An indicator system as claimed in claim 1characterized in that said power supply is adapted to supply impulses ofalternating polarity to drive said stepping motor, said stepping motorswitch means consisting of thyristors connected in anti-parallel.
 8. Anindicator system as claimed in claim 1 characterized in that said powersupply is adapted to supply impulses of alternating polarity, saidstepping motor switch means comprising a two way thyrisTor (triac). 9.An indicator system as claimed in claim 1 comprising a row conductor foreach row of signal indicators, each signal indicator having first andsecond row switch means for each row, the first row switch meansconnecting the respective row conductor to a predetermined first voltagepotential and the second row switch means connecting the respective rowconductor to a predetermined second voltage potential of said powersupply, said release magnet being adapted to actuate only said steppingmotor switch means upon actuation by said first voltage potential andbeing further adapted to actuate both the stepping motor switch meansand said release magnet upon actuation by said second voltage potential.10. An indicator system as claimed in claim 9 wherein said steppingmotor switch means and the release magnet are connected in a manner suchthat the stepping motor switch means are actuated in response toenergization of either polarity and the release magnet is actuated onlyin response to energization of a single polarity.